Problem with Prefab script

Questions & Answers
1

I created an enemy object name “bat” and wrote a script that make “bat” can follow player.This game object working well. But when i turn that enemy object as a prefab, this prefab can’t follow player as game object did. Unity show this error: “UnassignedReferenceException: The variable hero of bat_controller has not been assigned. You probably need to assigned the hero variable of the bat_controller script in the inspector”.
Here is my code:

public Transform hero;
public float force;
private Rigidbody2D rb;
private Vector3 movedir;
private Vector3 batscale;

public float speed;
private void Awake()
{
    rb = GetComponent<Rigidbody2D>();
}

void Start () {
    batscale = transform.localScale;
}

void Update () {
    movedir = (hero.position - transform.position).normalized;
    transform.Translate(movedir * Time.deltaTime * speed);

    if (hero.position.x < transform.position.x)
    {
        transform.localScale = new Vector3(batscale.x, batscale.y);
    }
    else if(hero.position.x > transform.position.x)
    {
        transform.localScale = new Vector3(-batscale.x, batscale.y);
    }
}
2

I bet you assigned “hero” property via inspector on scene. Prefab cannot reference scene objects.
You should find hero on scene with some other way. For example you may add this in Start function:

hero = FindObjectOfType().transform;

or whatever script you using with Player GameObject instead of Hero. Or find with tag

3

Thank you ^^ It works